What is infrared light? Infrared waves are a portion of the light spectrum that follows red. They have longer wavelengths than visible light, ranging from 700 nanometers to one millimeter. This renders them invisible to humans in almost all conditions.
Visible light is the light that we can see, and thus is the only light detectable by the human eye. White light is visible light, and it contains all the colors of the rainbow, from red to violet. The range of visible wavelengths is 400 to 700 nanometers.
All electromagnetic waves: are transverse
waves; can travel through a vacuum ; travel at exactly the same speed in a vacuum, the speed of light, 300,000,000 m/s.
Like all waves, electromagnetic waves:
- transfer energy from one place to another;
- can be reflected;
- can be refracted .
Each color corresponds to a certain wavelength of light in the electromagnetic spectrum. Our eyes are only privy to a very limited range of these wavelengths, which we call 'the visible spectrum. ' This essentially means that, just outside of eyeshot is a whole world we can't see or experience.
Receiving Electromagnetic WavesAn antenna for receiving EM signals works in reverse. And like antennas that produce EM waves, receiver antennas are specially designed to resonate at particular frequencies. An incoming electromagnetic wave accelerates electrons in the antenna, setting up a standing wave.
Electromagnetic radiation is made when an atom absorbs energy. The absorbed energy causes one or more electrons to change their locale within the atom. When the electron returns to its original position, an electromagnetic wave is produced.
The visible light spectrum is the segment of the electromagnetic spectrum that the human eye can view. More simply, this range of wavelengths is called visible light. Typically, the human eye can detect wavelengths from 380 to 700 nanometers.
Generally speaking, we say that light travels in waves, and all electromagnetic radiation travels at the same speed which is about 3.0 * 108meters per second through a vacuum. We call this the "speed of light"; nothing can move faster than the speed of light.
The Speed of EM Waves in a VacuumIn 1 second, an EM wave can travel a distance greater than 7 times the distance around Earth. Even at this speed, rays from the Sun take about 8 min- utes to reach Earth.
Electromagnetic waves are waves which can travel through the vacuum of outer space. Sound waves are examples of mechanical waves while light waves are examples of electromagnetic waves. Electromagnetic waves are created by the vibration of an electric charge.
The electromagnetic waves are not mechanical waves. There are vibrations of electric vector and magnetic vector in them. These vibrations do not need any particles present in the medium for their propagation. That's why electromagnetic waves do not require any medium for propagation.
Radio waves, gamma-rays, visible light, and all the other parts of the electromagnetic spectrum are electromagnetic radiation. Electromagnetic radiation can be described in terms of a stream of mass-less particles, called photons, each traveling in a wave-like pattern at the speed of light.
This range is known as the electromagnetic spectrum. The EM spectrum is generally divided into seven regions, in order of decreasing wavelength and increasing energy and frequency. The common designations are: radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma rays.
Electromagnetic waves are waves that consist of vibrating electric and magnetic fields. They transfer energy through matter or across space. The transfer of energy by electromagnetic waves is called electromagnetic radiation. This causes a vibrating electric field, which in turn creates a vibrating magnetic field.
Radio waves are much bigger than light waves (in terms of their wavelength). Radio waves are bigger then the size of atoms in a wall, that is why they go through, while light is a small wave and cannot get through the wall. If the wall is made out of glass, LIGHT WILL go through it.
Fields in excess of 109 Gauss, however, would be instantly lethal. Such fields strongly distort atoms, compressing atomic electron clouds into cigar shapes, with the long axis aligned with the field, thus rendering the chemistry of life impossible.
While they're generally safe, the NCCIH warns that magnetic devices can be dangerous for certain people. They caution against using them if you also use a pacemaker or insulin pump, as they might cause interference.
A continuous exposure limit of 40 mT is given for the general public. Static magnetic fields affect implanted metallic devices such as pacemakers present inside the body, and this could have direct adverse health consequences.
The magnetic field of Earth is caused by currents of electricity that flow in the molten core. These currents are hundreds of miles wide and flow at thousands of miles per hour as the earth rotates. The powerful magnetic field passes out through the core of the earth, passes through the crust and enters space.
This is due to the finding (discussed above) that whole-body human absorption of RF energy varies with the frequency of the RF signal. The most restrictive limits on whole-body exposure are in the frequency range of 30-300 MHz where the human body absorbs RF energy most efficiently when the whole body is exposed.
Electricity is everywhere, even in the human body. Our cells are specialized to conduct electrical currents. Almost all of our cells can use these charged elements, called ions, to generate electricity. The contents of the cell are protected from the outside environment by a cell membrane.
